I've seen this film in both regular and IMAX projections, and if you enjoyed it in regular, you owe it to yourself to spend the extra effort/money to see it in IMAX. It is an immersive, awesome movie-going experience that cannot be replicated any other way. The sound is loud, the picture is gorgeous, it's everything seeing an epic film in a theater should be. The changes to the IMAX-size image aren't jarring, but you feel more connected to the picture every time it expands.
I certainly hope that besides the January Oscar push, that they decide to re-release this film every few years in IMAX, because I (and many others, I'm sure) will never tire of that experience.